Automatic signaling system for electric railways



No. 751,021, P'ATENTED FEB. 2, 1904.

H. B. SNELL. AUTOMATIC SIGNALING SYSTEM FOR ELECTRIC RAILWAYS;

APPLIOATiON FI'LBD Arm-25,1903. 1&0 MODEL. 2 SHEETS-SHEET 1.

b. fifwaz 53%? M 'PATENTED FEB. 2,1904.

v H. B.'SNBLL. AUTOMATIC SIGNALING SYSTEM FOR ELECTRIC RAILWAY APPLICATION FILED APR. 25, 1903.

I 2 SHEETS-SHEET 2.

N0 MODEL.

VA l C WfWfiifi @zfuz UNITED STATES Patented February 2, 1904.

PATENT OFFICE.

HARRY B. SNELL, OF CEMENT CITY, MICHIGAN, ASSIGNOR TO THE SNELL ELECTRIC SIGNAL COMPANY, A CORPORATION OF MICHIGAN.

AUTOMATIC SIGNALING SYSTEM FOR ELECTRIC RAILWAYS.

SPECIFICATION forming part of Letters Patent No. 751,021, dated February 2, 1904.

Application filed April 25, 1903.

To all whom it may concern.-

Be it known that I, HARRY B. SNELL, of Cement City, county of Lenawee, and State of Michigan, have invented certain new and useful Improvements in Automatic Signaling Systems for Electric Railways; and I do hereby declare that the following is a full, clear, and exact description of the invention, which will enable others skilled in the art to which it appertains to make and use the same,refere nce being had to the accompanying drawings, and to the characters of reference marked thereon, which form part of this specification.

My invention has reference to an automatic signaling system for electric railways, and the same is particularly adapted to be employed on suburban electric lines to indicate whether a block or section of track between two turnouts is clear, so that it may be entered by an approaching car, and if the track is not clear the same will indicate so long as there remains a car upon the particular section which it is desired to enter.

In carrying out my invention I employ a simple arrangement of circuits and simple and effective mechanisms adapted to operate in conjunction therewith, all of which will be pointed out in the following specification when taken with the accompanying drawings, in which- Figure 1 is a view, partly diagrammatic in character, showing the arrangement of the circuits and also showing the operation of the trolley-actuated switchesadapted to control said circuits. In this view are also shown the mechanisms which operate to close the local signal-circuits. Fig. 2 is a side elevation of one of the trolley-actuated three-way switches employed in carrying out my invention. Fig. 3 is an end elevation of one of the switches, the section being on line a m, Fig. 2. Figs. L and 5, respectively, are views illustrating the operation ofthe three-way switches At each end of ,a block or section of track between two turnouts is provided a box 1, containing mechanism adapted to close a local signal-circuit whena car has entered upon the section. The mechanism in each box comprises a ratchet-wheel 2, rotatably mounted teeth upon the ratchet-wheel.

Serial No. 154,194. (No model.)

upon a shaft 3. This ratchet-wheel is preferably arranged with oppositely disposed ratchet-teeth 4: and 5, respectively, adapted to be engaged by suitable gravity-pawls 6 upon the ends of pivoted arms 7 and 8, carrying setting and restoring magnets 9 and 10, respectively, said arms being raised when the circuit through the respective magnets carried thereby is closed. By the arrangement disclosed the magnets are pivoted while the armatures are fixed, although the reverse arrangement may prevail, it being obvious that the magnets may be fixed and the armatures pivoted, the latter being provided with pawls upon their free ends adapted to engage the It will be apparent that repeated closing of the circuit through one of the magnets will cause the intermittent rotation of the ratchet-wheel in one direction, and that if thereafter the circuit through the other magnet is closed repeatedly an equal number of times the ratchet-wheel will rotate in a reverse direction and assume its original position. I have indicated in the drawings a single ratchet-wheel having oppositelydisposed teeth; but it is apparent that this arrangement is equivalent to two separate ratchetwheels secured upon the same shaft side by side with their teeth arranged in opposite directions. Upon the shaft which carries the ratchet-wheel is also secured a disk 11, having a marginal recess adapted to receive the end of a rod 12, longitudinally movable in suitable guides and held against the edge of the disk by a coiled spring 13. The lower end of the rod 12 is adapted to enter between the free ends of contact-fingers 14 and close the circuit containing the signal lamps or any other suitable signal device. In its normal position, however, (shown on the left, Fig. 1,)the rod 12 will be raised out of contact with the fingers 14, the upper end thereof being in the recess of the disk 11,'the signal-circuit being as a consequence open. Any other form of circuit-closing device depending for its operation upon the action of oppositely-arranged ratchets actuated by set ting and restoring magnets may be employed instead of the device herein described. At each end of the section of track is also provided a three-way switch or circuit-controller, a preferred form of the same being shown in Figs. 2 and 3. As shown, each switch comprises a base-plate 15, arranged at the ends with suitable clamps 16 for mounting upon the trolleywire, and journaled centrally of the base-plate through an opening therein is a cylinder 17, provided with a downwtrdly-extending bifurcated plate 18, adapted to take aposition above and on each side of the trolley-wire, so as to be engaged by the moving trolley-wheel, the altered positions of the plate and cylinder 17 i when the car is running in opposite directions being shown in Figs. 4 and 5, while the normal position of the plate and cylinder is shown in Fig. 2, being returned to this position by gravity after being operated by the trolley. 19, 20, and 21, respectively, are contact-strips mounted at one end upon an insulated block 22, the connections to the strips being made by means of binding-screws 23. The free ends of the contact-strips are provided with inclined contact-shoes, made of any suitable insulating material and adapted to contact with the face of the cylinder 17 and be held in raised position out of contact with the vertical posts 24, 25, and 26. The post 25 is insulated from the body of the switch, whereas the two outer posts are integral with the base, and consequently electrically connected therewith and with the trolley-wire. In the face of-the cylinder 17 are provided recesses 27, which the shoes upon the ends of the contact-strips are adapted to enter, the arrangement being such that only one shoe can enter one of the recesses at a time. When the parts are in the position shown in Fig. 2, the contact-strip 20 will take a lowered position in contact with the post 25, one terminal of the circuit connected therewith being secured by means of the binding-screw 23 and the other being secured to the lower end of the post 25. The other circuits adapted to be controlled by the switch lead directly from the trolley-wire, and the two outer posts 24 and 26, respectively, are therefore not insulated. When the parts take the position shown in Fig. 4, the circuit through the contact-strip 19 will be closed, and in like manner when the parts are in the position shown in Fig. 5 the circuit through the contact-strip 21 will be closed.

It will be apparent that the parts may be insulated in various ways from that described. For instance, all of the contact-posts beneath the contact-strips of the switch may he insulated, in which case the insulated shoes at the free ends of the contact-strips maybe dispensed with.

Other forms of three-way switches arranged with a depending plate adapted to be actuated by a moving trolley may be employed in the operation of my improved signal system.

Having now described the preferred mechanism adapted to be employed in carrying out my invention, the wiring for operating the same will be readily understood by reference to the diagram of the same shown in Fig. 1. The trolley-wire carrying the current-supply is indicated at 26. 27 and 28, respectively, are local circuits containing suitable lamps 29 and 30, respectively, or any other suitable signal devices adapted to indicate whether the track is clear or whether it is occupied. These local signal-circuits leading from the trolley-wire through the signals to the ground, as shown, are adapted to be opened and closed by the operation of the signal mechanisms located at the end of the block, and the same are entirely independent of the line wires or circuits leading from end to end of the block. 31 is a line-wire extending from end to end of the block and leading to the contact-strips 19 and 20 of the three-way switches. At 32 are shown the connections of the trolley-wire with the posts 24, adapted to contact with the strips 19 of the switch and to admit the current from the trolley-wire into the line-wire 31 when the bifurcated plate of either switch has been moved from the position a. 33 represents wires leading from the contact-strips 20 through the setting magnets 9 to the ground. When the three-way switches are in their normal position, there will be a complete circuit from the ground on the left through the wire 33, leading through the magnet 9, the contact-strip 20, the line-wire 31, the contact-strip 20 on the right, and the wire 33, leading through the magnets 9 on the right to the ground. 34 is a second line-wire extending the entire length of the block and connecting with the contact-strips 21, adapted to admit current into said line-wire from either end when the contact-plate of either switch assumes the position b. 35 represents wire-leads extending from the ends of the line-wire 34 through the restoring-magnets 10 to the ground.

The operation of my improved system is as follows: As the car enters the block on the left the trolley-wheel will contact with the bifurcated plate of the three-way switch at this end of the block and cause it to take the position a momentarily, thereby opening the line 31 through the contact-strip 20 and admitting current into the same from the trolley-wire by closing the circuit through the contact-strip 19. The effect of this operation will be to send an electrical impulse along the line-wire 31, as indicated by the heavy line in the diagram, and energize the setting-magnet 9 of the signal mechanism on the right and cause the arm carrying said magnet to be raised to the position indicated in dotted lines, and because of the pawl on the end of this arm the ratchetwheel will be rotated to the left the distance of a single tooth. The operation of the signal mechanism will close the local lamp-circuit on the right, and the signal contained in said circuit will indicate that the block is occupied. After the car has passed the switch on the left the bifurcated plate of said switch will again end will, because of contact with the moving trolley, be moved to the position I) and current will be admitted from the trolley-wire into the line-wire 34 by the closing of the contact-strip 21. This will cause the current to pass through the wire-leads 35 and through the restoring-magnets 10, the arms carrying these magnets being lifted momentarily as a result of the same. The pawl upon the ends of the arms carrying the magnet 10 of the mechanism on the right will engage the ratchet-wheel and rotate the same the distance of one tooth in a reverse direction to that which it had been rotated by the previous operation, and the parts will again be in their normal position, the local lamp-circuit being opened by the operation and the signal contained in said circuit extinguished or otherwise altered in any suitable manner to indicate that the block is clear. The raising of the restoring-magnet 10 on the left simultaneously with that upon the right will have no effect upon the ratchet-wheel or the mechanism on the left, since the first tooth upon said wheel which would be engaged is cut away, so that the ratchet-wheel is not operated in a reverse direction until the magnet 9 has first caused it be rotated to turn on thesignal-circuit. This arrangement is duplicated in the mechanism on the right. e will now assume that a number of cars have entered upon the block. As each car enters thereon the switch on the left will be actuated, and instead of one impulse a number of impulses equal to the number of cars entering the block will be sent along the line-wire 31, causing the magnet 9 on the right to be raised an equal number of times, so that the ratchet-wheel on the right will be rotated a distance corresponding to the number of cars which have entered upon the block. As each car leaves the block the restoring-magnet 10 on the right will be lifted, causing the ratchet-wheel to be intermittently rotated in a reverse direction, so that after all the cars have left the block the signal on the right will again indicate that the block is clear. Should a single car or any number of cars enter upon the block and then back off, it will be observed that the effect upon the mechanisms will be the same as if such cars had continued to pass along the block and leave the same at the opposite end. As the connections to the switch and to the signal mechanism at each end of the block are the same, being, however, arranged in reverse order, the action of the various parts will be the same whether the cars enter the block from the right or the left.

From the foregoing description, by which the complete operation of my inventionshould be made clear, the many advantages thereof should be apparent. Among other valuable features it should be observed that the linewires are at all times inactivebeing open circuits-except when the switches at the ends of the block are momentarily engaged by the moving trolley. The line-wires willtherefore be active for an instant only, permitting the use of wires of very light gage-an advantage which is obvious.- Furthermore, the action of the mechanism adapted to control the signal-circuits is not dependent upon closed circuits or a continuous currentsupply, the operation of the various devices being unafiected should the current in the trolley-wire be shut off. vThis is a feature of inestimable value in a system of this character.

Having described my invention, what I claim, and desire to secure by Letters Patent, 1s

1. In an automatic block-signal system, the combination with the trolley-wire carrying a current-supply, of trolley-actuated switch devices located at the ends of a block, each provided with three ways for current to pass, local signal-circuits at each end of the block, mechanisms adapted to control said local circuits, magnets 9 and 10 adapted to be independently operated to actuate the signal mechanisms, the line-wire 31, connections leading therefrom through the setting-magnets 9, the

line-wire 34-and connections leading therefrom through the restoring-magnets 10, whereby when a car enters the block the connection leading through the setting-magnet 9 of the mechanism at the end at which the car enters is broken and the current from the trolleywire is closed into the line-wire 31; and as the car leaves the block the current is closed into the line-wire 34 and the connections leadingtrolley-wire carrying a currentsupply, -trolley-actuated switches at each end of the block having three current-ways 19, 2O and21,adapted to be closed one at a time only, the currentways 19 and 21 when closed admitting current from the trolley-wire, local signal-circuits at each end of the block, a mechanism for operating each of said circuits embodying a rotatable ratchet-wheel having two sets of oppositely-arranged teeth, pivoted armatures carrying pawls adapted to engage the teeth upon said ratchet-wheel, setting and restoring magnets 9 and 10 carried by said armatures adapted to be independently energized so as to operate the ratchet-wheel in alternate directions, a line-wire 31 connected at its ends to the our- ISO rent-Ways 19 and 20, connections leading from the current-ways 20 through the setting-magnets 9, the line-Wire 34 connected at its end to the current-Way 21, and connections leading therefrom through the restoring-magnets 10, whereby the signal mechanism at the end of the block opposite to that at which the car enters will be actuated to close the local signal-circuit controlled thereby, and said mechanism 10 will again operate to open said signal-circuit as the car leaves the block, substantially as described.

In testimony that I claim the foregoing as my own I aifix my signature in presence of two Witnesses.

. HARRY B. SNELL.

\Vitnesses:

TM. G. GARoTHERs, CARL H. KELLER. 

